#include<stdlib.h>
#include<stdio.h>
#include<math.h>
int main(void)
{
	int n, m,i;
	double sum;
	scanf("%d%d", &m, &n);
		for (i = m; i <= n; i++)
		{
			sum = pow(i, 2) + 1.0 / i;
	}
	printf("sum = %.6lf", sum);
	return 0;
}
